I might be able to help a bit.. as I lived in in the States for 4 years and actually found it really hard to adjust to the food there... I put on like 15kg in the first 2 years and then proceeded to lose about 20kg in the 3rd and 4th years! haha (probably due to me having a Brazilian acrobat friend pushing me to get healthy
One thing they don't have over there is our style of sausages.... they have so many types over there, from the humble hot dog (which you should never eat for health reasons - trust me) to polish kielbasa.
I worked in a Brazilian restaurant in Florida and they even had Aussie Rump imported because it's the best for their "Picanha"
anyway..
I started making Meat pies at home because they think savoury pie is weird. Sausage Rolls also aren't there.
Custard is not there... we had a visiting friend bring over custard powder!
Works Burgers... this is something they find weird, with fried egg, mushroom, beetroot (pickled beets - very aussie), pineapple and well... anything you can find to slap on the bun!
Kebabs - although not "australian" I think for a country only 200 years old we can adopt some things... USA have something similar called Gyros (heros) but ours are definitely different and better IMO.
Ginger Beer!! They have what we call ginger ale and I did find in the World Market, cartons of Bundaberg ginger beer! so I grabbed a couple of slabs... I also found the West Indians make the same stuff, although usually a LOT stronger and burnier... hah
That's all i can think of for now